Kiln heating



Oct. 20, 1931.

P. D' H. DREssLER KILN HEATING Filed March 16. 1928 s sheets-sheet` 1 INVENTOR PH/L/P D WEL-551.511

B fg A ATTORNEY Oct. 20, 1931.

P. DH. DRESSLER KILN HEATING Filed March 16, 1928 3 Sheets-Sheet 2 ATTORNEY Oct. 20, 1931. P. D'H. DREssLER 1,328,492

KILN HEATING Filed March 16. 1928 3 Sheets-Sheet 3 x\ I Y lNvEN'roR Patented Oct. 20, 1931 I UNITED STATES yPxrela'r oer-lcs PHILIP DHUG DRESSLER', OiE CLEVELAND, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS,

T SXVINDELL-DR-ESSLER CORPORATION,

POBATION OF PENNSYLVANIA OF PITTSBURGH, PENNSYLVANIA, .A` CORL KILN HEATING Application led March 16, 1328. Serial No. 262,221.

The general object of the present invention of the underfeed type.

coal', and especially slack coal or is the provision of a continuous'tunnel kiln with/improved kiln heating means. More specifically, the object of the present invention is to provide a continuous tunnel kiln with simple and effective means for burning other cheap solid fuel, in combustion chambers distributed along 'the length of therfiring zone of the kiln in vsuch manner as to insure a desirable uniformity in combustion conditions and Vother desirable kiln operating conditions.

In the preferred practical mode of carry-v ing out the bustionchamber with an automatic stoker of the under-feed type. It is one ofthe advantages of my invention that the stoke'rs employed may well be wholly or in large part of standard construction and-design, but my adaptation of stokers to the combustion chambers of a continuous tunnel kiln is characterized byvarious novel features of construction and arrangement contributing to convenient andefl'ective utilization of such stokers. 1

Aside from the special advantages of particular featuresof construction and arrangement employed in the preferred embodiment of my invention, certain importantv general advantages are obtained by employing automatic stokers, and particularly automatic stokers of the underfeed type, in firing a continuous tunnel kiln.' The use of such stokers makes it practically feasible to-burn slack coal or analogous cheap solid fuel in -kiln combustion chambers, under conditions, and particularly in firing certain wares, which have not permitted the usefof'such fuel heretofore made possible by the use of automatic Stoke-rs.

tinuous feed of the coal, its volatile con'- tinuous and moreor less uniform rate and largely cracked and burned inthe combus tionA chamber, particularly if the stokers are In consequence, the rush into the kiln chamber of unburnedrich gases of distillation,

tion of open fired tunnelkillnswith hand firinvention I provide each com-- preciably above that of their proper distribution in the kiln,

Vith the slow `but normally con-V following each firing. operation, which 1s experienced 1n, the operaing is avoided. A most important advantage of theI` invention is the great uniformity in combustion conditions which it is possible to maintain.

With hand firing it is necessary to main tain an approximate equality between the combustion chamber pressure andthe pressure of the atmosphere to avoid the outrush of flame, or the inrush of cold .air when the lire doors areopened, as theyniust be at frekiln.` In particular, it is feasible and in many cases desirable to maintain a gas pressure 1n the combustion chamber which 1s apthat the heating gases `may be passed into the kiln chamber at high velocity facilitating without requiring an objectionable minus pressure in "the latter.v

It has long been recognized that a continuous tunnel kiln possesses a great inherent advantage over anintermittent kiln from the standpoint of fuel economy, but for many purposes, as in burning bricks gous operations, it has not been possible heretofore to fully realize this advantage, because to insure kiln operating conditions necessaryvfor production of a high grade product, it has been necessary to use a relatively expensive fuel, as oil or clean gas. With the present invention, however, it is possible to burn slackV coal, which ordinarily is the cheapest possible' fuel, efliciently, and with the maintenance of the kiln operating conditions required for` the production of high grade wares, andheretoforecbtainable only with more expensive fuels such as oil or clean producer gas.

The various'features ofnovelty whichcharacterize my invention are set forth with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, itsadvantages and specific objects at# tained :with its use, referenceshould behad the atmosphere, so

and in analo- Cil n r al) to the accompanying drawings and descriptive matter in which have illustrated and described preferred embodiments of the invention.

Of the drawings:

Fig. l is a. plan view of a. portion of a tunnel kiln;

Fig. 1A is a somewhat diagrammatic side elevation of a portion of the kiln;

Fig. 2 is an elevation in section on the line 2 2 of Fig. l;

Fig. 3 is a section on the line 3-3 of Fig. 1 and Fig. 2;

Fig. l is a section on the line l--l of Fig. 3;

Fig. 4A is a partial section taken similarly to Fig. l illustrating .a modified construe-- tion;

Fig. 5 is a section on the broken line 5-5 of Fig. ll; and

Fig. G is fasection on thebroken line 6-6 of Fig. 3. Y

In the drawings, A represents a continuous tunnel kiln through which bricks, or other wares to be fired, are continuously movedon `kiln cars B running on track rails A. As conventionally illustrated, each car is Aprovided with perforated platform parts B forming the top walls of channels B2 between the piers `supporting .the platform parts B, the channels B2 leading from the outer side edges of the -car toward the longitudinal center line of the latter. As shown, the kiln, which is of the Aopen fired type, is heated by hot burning gases .and products of combustion passing into the kiln chamber from the ycombustion chambers 'C distributed along the length of `the firing or high temperature Zone of the kiln and arranged at both sides of the latter.; As shown, earch combustion chamber C communicates with the kiln chamber through a :corresponding port A2 which .advantageously is downwardly inclined and located atsuch a level as to discharge gases into the adjacent outer ends of the car channels B2.

Each combustion chamber C is supplied with fuel by a corresponding underfired stoker mechanism D.' As shown, thestokermech- .anism comprises a metallic body portion eX- tending into the corresponding combustion chamber C through a suitable wall opening C. Each stoker mechanism is formed with a fuel trough or channel D2, and a wind-boxfDS. The portion of the fuel trough D2 passing through the wall ofV the combustion chamber is circular in cross section, and a coal feeding device', shown .as a conveyor screw D, is provided to advance coal from .an external `coal hopper D4 into vthe combustion chamber through the channel D2 at suitable rate fixed by the rate of .rotation of the screw D. The fuel channel or retortDgfis open at its upper sidel for approximately 'the full length of Athe combustion chamber; and the -coaladvanced bythe feed- Advantageously, however, 'instead of the simple dumping grate construction illustrated in Figs. 4 and 5, I may employ clinker breaking grates as shown in Fig. 4A, in which each shaft E carries parts EA replacing the parts E of Figs. Ll and 5, and each provided with clinker breaking projections The latter cooperate with side Wall plates E and E7 to 'break up clinkers and to work the elinkyers and ashes into the ash-pit when the shafts' E arerotated.

A characteristic featureof the preferred .construction illustrated, is that the axis of feach Stoker, i. e., the direction of the fuel feed,v is parallel to the axis of the kiln. This 90 makesit possible Vto provide ash pit cleaning door openings F', and door openings F2 through which the fire may be dressed and .clinker removed from time to time if necessary, at one end of each combustion chamber, and to locate the coal hopper D and actuating mechanism of the corresponding stokeratthe vopposite end of the combustion chamber. Each opening F and F 2 is normally closed by a corresponding door f or f2, respectively.

To permit the rea dy removal of each stokcr .D when this becomes necessary for repairs o-r other purposes, each stoker is slidingly mounted on a. Wear plate A4L mounted on a' pier A3 extending into each combustion chamber through the corresponding opening C', suitable provisions being made to seal the opening C when the stoker ris in place, these provisions including the removable metalparts D14 and D15 to which reference is hereinafter made.

To `facilitate the insertion and removal of the stoker, the `air supply connection to the wind box D3, if air is to be supplied under pressure asis ordinarily desirable, should be readily ydetachable from the Stoker. As shown, the air supplied to the Stoker wind boX D31for each combustion chamber, passes through a corresponding con duit G imbedded in the foundation of the combustion chamber and having an uprising discharge loutlet G which opens 'to the wind 'box through a port D5 inthe bottom wall of the latter in the Aassembled condition of the apparatus. The inlet 4end G2 of the pipe G extends up above t e surface ofthe foundation at one end ofthe combustion chamber, and is connected to a Vblast supply pi )e system Gg, receiving air from ablower 1". The air supplied .to 'the wind box D3` passes from the latter through ports D? formed in or between removable tuyre sections D7 which form the upper -sides of the coal channel or retortDZ,

'and partly through suitable 'damper Vregu- E, and through theV coal andy ashes on the grates.

In addition to the primaryv airfor combustion supplied `to each combustion chamber throughthe pipe G, secondary'air for combustion isadvantageously 'passed into the combustion chamber through' ports A5 in the Vouter side wall of the combustionchamber,

from an air preheating and combustion chamber cooling system. yThat system, as shown,

comprises .an inlet pipe g imbedded in the foundation portion of the corresponding kiln side wall, and supplying air at g to a hori- Zontal channel H extending under the corre,- sponding port A2 and having uprising por tions Hjat the sides of the chamber and a top portion H2 above the port A2 which communicates with the cooling' space C5 in the `hollow roof of the combustion chamber.

The roof space'G is connected by vertical channels or iues 'G6 to horizontal channels C7 and Cainthe end walls of the combustion chamber. The channels C7 and C8 communicate with a channel or space C9 in the outer -side wall of the combustion chamber. The s aceCfis of arch form andsupplies air to t e ports A5 through anair chamber C10 from open. i The passage of air from the channel yC9 into the chamber C1"k maylbe .regulated by a slide brick or damper C12.. An exhaust port 'C15 controlled by a slide brick or damper Cl-t permits excess air employed in cooling'the walls of the combustion chamber to escape into the.- atmosphere, when more air is needed for cooling than is required forfsecondary combustion.

It will be understood that the joints between the'various damper and door openings and Athe corresponding dampers and doors, may be normally lutedwith iire clay or otherwise made tight in accordance `with the usual practice in the furnace art. combustion chambers .may be provided with the usual accessories and parts such as pyrometer wells C15 and normally closed inspection openings C16 and C17.v

The air supplied to the inlet end g2 of each pipe g may be furnished by the blastpiping system GrgV which supplies air to the wind boxes D3 of'theistokers D. In some cases both the primary and the secondary air may be atmospheric air sucked into the kiln by the stacks or induced draftV fans (not shown), employed in the usual manner to create the desired draft through the kiln'. `It is one Vof the advantages of the'present invention, how# ever, that a pressure above that( of thev atmos- Furthermore, the

phere may be maintained in the different comj bustion chambers when this is desirable. The

.maintenance of such a combustion chamber pressure requires, of course, that the air supplied by the pipes G and g should be under a7 pressure above that of the atmosphere. .The

maintenance of a pressure above thatof the Vacter may be employed. The primary regulation may advantageously be effected by means of orifice Aplates g5 and G5 having oriice 'openings of proper size, which are inserted in the individual connections from the pipe system Gg to the various pipes g and G.

Each Stoker comprises a mechanismcDl" including an oscillating ratchetlever D11 for rotating'the screw D. This mechanisnimay be, and as shown, is of known adjustable type. f The latter is givenV an oscillatory movement by a corresponding connecting rod I and eccentric'I'. The eccentrics I for the different stokers at each side of the kiln are mounted von a corresponding lay shaft I2. As shown, the mechanism for rotating the two lay shafts 12,*one at each side of the kiln, comprise a driving motor J mounted on theroof of the kiln chamber and connected to the shafts I2 through speed reducing and `speed changing lgearing shown as including a speed changing device K of the well known Reeves drive type, a slow speed shaft L, and sprocket chains L connecting the slow speed shaftL tothe shafts I2.

D enter successive combustion chambersC at each side of the kiln, at opposite `ends 'of the combustion chambers C, so that the coal hoppers D4 for an adjacent pair of combustion `chambers C are located in the space between those combustionchambers,and so that the ash pit doors for each intermediate combus tion chamber `face theashpit doors of an ladjacent combustion chamber. This arrange L ment separates the fuelV supply systemsfor each combustion chamber from the ash removal' system from that or `any adjacent and tuyereV sectional The renewal ofthe i l i Advantageously, and as shown, the stokers grates can be affected with comparative ease .and rapidity whenever such renewal becomes necessary, as the doorways F2 permit convenient access to the grate bar and may be made i 5 as conditions require.

.' 10 justed, when occasion requires through the doorways F2 normally closed by the doors f2. vEach stoker may be quickly removed and replaced by another when major repairs are required.` The stoker parts most liable to f '15 injury are the tuyere sections D7. As shown,

these sections are connected to the body portions of the wind box and retort walls `by tongue and groove joints which permit the tuyere sections to be slid into and out of place F through the opening in the combustion cham- -ber end wall normally closed by the parts DM and D15. In consequence, a tuyere section which 'fails can be readily replaced without 'removing the stoker mechanism after removing the parts D14 and D15 for the purpose. The parts D14 and and D15 are metal parts which are normally held in place by separable resilient ties or connectors D16.

The described construction thus not only permits of the ready adjustment or renewal of vgrate bars and tuyre sections but also permits of other minor stoker adjustments and repairs.

It will be apparent to those skilled in the art that the present invention can be applied to various types of tunnel kiln without modification in the design or construction of the latter except that required for the addition of `the stoker mechanisms and the addition of suitable primary and secondary air supply connections to the combustion chambers when such connections are not already present in the type of kiln to which the invention is applied. j

It will also be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention as set forth in the appended claims and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

Having nowdescribed my invention, what- I claim as new and desire to secure by Letters Patent, is

l. The combination in a continuous kiln having a kiln chamber with an inlet at one end and an outlet at its opposite end for the insertion and removal of material treated in the kiln chamber and means for moving said material through the kiln chamber Vfrom said inlet to said outlet, of a plurality o f `Icombustion chambers at the sides of the kiln chamber for supplying heated gases to the latter at points distributed along the length Lezama of the kiln chamber between said `inlet and outlet, and automatic' stoker-s 'for feeding solid fuel. int-o the different combustion chambers.

2. The combination 'in acontinuous `tunnel kiln having a kiln chamber and a plurality of .combustion chambers distributed along fthe sides of the kiln chamber and separately =de livering hot gases thereto and automatic stok ers one for each of said combustion chambers and each adapted to feed solid fuel into -the corresponding combustion chamber.

3. In a continuous open lire tunnel kiln having combustion chambers at the sides of the kiln chamber, the improvement Awhich consists in an underfeed stoker for each of said combustion chambers.

4. In a continuous tunnel kiln having a plurality of combustion chambers at one side of the kiln chamber, an individual stoker mechanism for feeding solid fuel into and maintaining a fuel bed in each of the different combustion chambers and a common 0perating mechanism for the different stokers.

5. In a continuous tunnel kiln having a plurality of combustion chambers at each side of the kiln, a separate stoker for feeding solid fuel into each combustion chamber, a

stoker actuating shaft at each side of the kiln, and a separate operating connection be- 7. In a continuous tunnel kiln having a plurality of combustion chambers at one side `of the kiln, each of-said combustion chambers having a stoker opening in oneof its walls transverse to the length of the kiln andl having `an ash removal openingin the Opposing wall transverse to the length of the kiln, and a stoker for each combustion chamber `feeding solid fuel into the latter through the corresponding stoker opening.

8. In a continuous tunnel kiln having a .plurality of spaced apart combustionchambers alongside the kiln .atene side ofthe latter and having a stoker opening and an ash removal opening formed the one in one, and the other in the second of the two opposing walls of each combustion chamber extending transversely to the length of the kiln, each intermediate combustion `chamber having its said stoker opening facing the stoker opening in an adjacent combustion chamber, and having its ash removal opening facing the ash removal opening in an adj acenty combustion chamber.

i 9. In a continuous tunnel kiln having a combustion chamber at the .side of the kiln "lia and a stoker adapted to feed coal into said combustion chamber in a direction parallel to the length of the kiln through a Wall of said combustion chamber extending trans-V versely to the length of the kiln.

10. In a continuous tunnel kiln having combustion chambers at the side of the kiln chamber, a stoker inlet opening in a Wall of each combustion chamber extending transversely to the length of the kiln chamber, a stoker extending into the combustion chamber through the said opening and comprising a fuel channel, and means for feeding fuel through said channel, grates Within the combustion chamber at the opposite sides of said fuel channel upon fwhich the fuel advanced through said channel falls.

11. The combination in a continuous tunnel kiln of combustion chambers at the sides of the kiln chambers, automatic stokers for supplying solid fuel to the diiferent'combustion chambers, and means for supplying combustion supporting air to said combustion chambers to maintain a gas pressure therein exceeding that of the atmosphere. Y

` tively.

14. In a continuous tunnel kiln having combustion chambers alongside the kiln proper and having an opening in one Wall of each combustion chamber extending transversely to the length of the kiln, an underfeed stoker extending into the combustion chamber through said opening comprising separable tuyre sections, and removable means for closing a portion ofsaid opening through which said tuyre sections may be replaced.

15. The combination in a continuous tunnel kiln of combustion chambers at the sides of the kiln chamber, and an automatic stoker removably mounted in each combustion chamber.

16. A continuous tunnel kiln having combustion chambers alongside the kiln with a stoker opening formed in the Wall of each combustion chamber, means providing a supporting track in each combustion chamber for a corresponding stoker on which the latter y may be slid into andout of place.v

17. A continuous tunnel kiln having combustion chambers alongside the kiln With a stoker opening formed in the Wall of eachV combustion chamber, a stoker provided with a Wind box for-each chamber, means providing a supporting track in each combustion chamber for the corresponding stoker on Which the latter may be slid into and out of place, and a blast conduit formed in the kiln sub-structure normally communicating With the Wind box of the corresponding stoker. Y

18. In a continuous tunnel kiln having combustion chambers distributed along its sides and automatic stokers one for and feeding solid fuel into each of said combustion chambers, a stoker operating shaft at each side of the kiln chamber above the corresponding combustion chambers and operating connections for the different combustion chamber stokers extending downward from each shaft into the space betvveen the corresponding side of the kiln chamber and the portions of the corresponding combustion chambers most remote therefrom and a driving mechanism for said shafts located above the kiln chamber.

19. In a continuous tunnel kiln having a plurality of combustion chambers at one side and automatic stokers one for feeding solid fuel into each of said combustion chambers,

a stoker driveshaft located above the combustion chambers and operating connections between the dierent stoker mechanisms and said shaft.

20. The combination in a continuous tunnel kiln comprising a kiln chamber and combustion chambers at the sides of the kiln chamber, automatic stokers one for each combustion chamber and adapted to supply solid fuel to the latter and to maintain a fuel bed therein, regulatable means for supply primary and secondary air for combustion to each combustion chamber at the under and upper sides. respectively of the fuel bed there- 1n Signed at Cleveland, in the county of Cuyahoga and State of Ohio, this 14th day of March, A. D. 1928.

PHILIP DHUC DRESSLER. 

